Sponges of the genus Clathrina Gray, 1867 from Arraial do Cabo, Brazil Author Klautau, Michelle Centro Federal de Educação Tecnológica de Química, Unidade Rio de Janeiro Rua Senador Furtado 121 - 125, Maracanã, 20270 - 021 Rio de Janeiro (Brazil) mkmt @ centroin. com. br Author Borojevic, Radovan Departamento de Histologia e Embriologia, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Caixa Postal 68021 21941 - 970 Rio de Janeiro (Brazil) radovan @ iq. ufrj. br radovan@iq.ufrj.br text Zoosystema 2001 23 3 395 410 journal article 10.5281/zenodo.5400552 1638-9387 5400552 Clathrina cylindractina Klautau, Solé-Cava & Borojevic, 1994 ( Fig. 7 ; Table 7) Clathrina cylindractina Klautau et al ., 1994: 372 , tabs 1; 2, fig. 2. TYPE MATERIAL . — Holotype , 20.VIII.1987 , coll. G. Muricy , The Natural History Museum , London ( BMNH 1999.9.16.21). TYPE LOCALITY . — Arraial do Cabo (Anjos), Rio de Janeiro , Brazil . ETYMOLOGY. — From Latin C ylindrus : cylinder. For the shape of the actines. MATERIAL EXAMINED. — Oasis Coralino. Forno, Anjos, several specimens collected under rocks and in small crevices. DESCRIPTION Specimens of this species are white in life and in alcohol. The cormus is very delicate, composed of large, irregular and loosely anastomosed tubes. Oscula are spread through the cormus and no water-collecting tubes are present ( Fig. 7A ). No special characteristics were found on the histological sections. The skeleton has no special organisation. It is composed of equiangular and equiradiate triactines ( Fig. 7B ; Table 7). Actines are straight, cylindrical to conical, with blunt ends. This species is very abundant in the Oasis Coralino, particularly on summer. Its habitat is sciaphilous and protected from the waves. Specimens can be found under rocks and other organisms, such as sponges, tunicates ( Ascidia ) and soft coral ( Palythoa ). REMARKS C. cylindractina is morphologically very similar to C. conifera n. sp. as previously discussed. However, their status as distinct, valid species was demonstrated by allozyme electrophoresis ( Klautau et al. 1994 ), showing that, even living in sympatry, they do not exchange genes.